Kinkted statei



rrsn sa aaasgann'r OFFICE.

Jo'sizPH scHEssn-s. or SAN FnAircIsco, CALIFORNIA.

fs'rmnT-P VEMENT A m '-TH-E METHCD F CONSTRUICV'ITINIGL'YQHE lgnown thatI, Josnrir Sennsnsn, a

(:1 rzen of the United 'States, a resident Q =.the city and, county ofSan Francisco,

-.- State of California, have invented certain newand usefulImprovements in Street- 'Pa emfents and the Method of Constructing Same,.of wh ich the following is a specifieate ,1 l ache invention relates tostreet pavements employing asphalt or similar i'ua'terialas a hinderiandparticularly to the wearing or topisurfaceiof street pavements.v

The object of the inyention to provide 1:5 ajstreet pave-mentwhich willnothecome smooth itndg slippery under. serv, i

@Anotherobject of the invention is to pro-- videastreetpave nent whichpossesses c0mparative permanency and stability.

furthe nobject of the invention is a) providea method ofl'aying a earingsurface 'uponxotherpavements. I

Theinvention.i-"possesses other, advantageous features which; with theforegoing, Will'be setfort'h at length in the following description 'l'ere outline in full that ition-which I-hare selected 1'de'seripti-onherein. The novelty the invention will be included in thecl aims sucb eeding said description. thisit will be apparent that 1--do not limit myself the "showing madeby said 'de 'wiption I may adoptmany"y'ariationswi i n of my invention forth in. said 5 Asphalt andsimilar pm" soon he some very smooth and in ervice,

dueto automol'iile trallic and the lubr cating oil' dropped by? thecountless 'autoinoli iles passing over'and standing on'the pavement. Thelubricating'oil unites iy'itlrthe asphalt a produces aharcl snr-face,hich become. "ye'ry smooth due tothe travel of rnhb r tired ysfh'eels,producing a ery dangerous pa einenhcy 'en in dry eather- In wet 1 .ther,thefsurfacefof the pavement h uses no slick that the driving of automoouthereover fbecoines dangerous and the .dririn of horses impossible. v i

.. [The pavement of tiny invention is of such character-'that'itpresents an even surface to trallic, but is not affected by lubricatingoils and does-not wear smooth and slippery, affording at all times andin all conditions of weather a perfect tractivc surface. The

pavement of my invention, which constitutes the Wearing surface, may beapplied as a" covering to smooth and dangerous asphalt pavements or tomacadamized,-:o11ed,"bricic, I granite, cement, slag, or basalt paye'm'ents.

which comes up fromlt'he'old Ii men th harder when cool.. The percentageoft'liese i Specification of'Lettcrsfatent. umn 'aaia Septcinlier15,1913. serial No. 739,908,

My invention relates to,. the"wearing so '1 face of the pavement and anys'uita-ble 1or available foundation o rrbase' therefor?maybe used,although I prefer to lay it over an asphalt pavement. g

The old pavement or Easels first cleaned in a suitable manner, andwhenit happens to be an asphaltpai'emengit is preferably,

though not necessarilyfheated tosoften the asphalt and reinove someiofthe' lubricatirig oil therefrom. The pavement is then given a.coating,'preferably a brush or spraycoat of hot liquidasphaltum,wliichlacts 'prir'icr" pally to hind the top surfaeeto the oldpave; ment. This asphal'thnrcoefiiiiQk the'n eoy-f ered. by a coating,prefera "lya brush or '75 spray coat of an asphalt compound or mixr;ture. This mixture consists :cr hotfliquid' asohalt containing groundlime r0 laste'r Y ofliaris, pumice stone, diatom ous earthf'orgroundslag. Itisfno't'ie 'n .hafallofitiothese materials be" used niiiitureiasseveral of those in'entione haveljequii'alent functions. The pumicestodiato'xnace earth and-slag absorb the lubricating oil" plaster of Pariscausesthe asphalt; to hedornie still when-cold and rawns-enhancer: ingmaterially under-pressure'a'nd the linie' stone acts as a filler toniiakeithe nii-Xtiir;set':

materials in the mixture ayb arigd* de pending'upon the base andltheroad conditions to 'be niet. 'Oi-er this cost Pplace a mineralaggregateicomposed principally of hrokenhard rock and limestone? F orthiss purpose I prefer -to use crushedliasalt or granite and lime stonein theproportion. of approximately fifty per c'e t. of each. Thisaggregate consists preferablyiof from (to, .175 per cent. of rock which\ij'illpasfs through a inch ring-but i" llheretained by a q1iar-.terincli ring'and" from QSitQAOp ercent; of rock which will pass througha quarter-inch. ring and he retained by an. eighthin ring. Thisaggrcgateis lieatediandf is distributed 105 over the second asphaltcoatin a, layer, preferahly one half or three'quarters of an. inch thick.The aggregate is theh' rolledlwith, a light hot'rollerz. The heatedrockshecoine embedded in thc'a sph'alt. coatings; \frhielrare ressedupward into the interstices between; the aggregate binding tliesa1ne,.lir1nly together. \Yhcn' this surface is applied to an old asphaltpavement, soxnc'of the asphalt ofthe old pavement which is softened-bythe heat is also forced upward between the pieces of the aggregate. Theaggregate may also contain a small proportion of the oxids of iron andmanganese which act as a flux to bind the rock and the asphalt toproduce a. homogeneous mass. The asphaltenters the pores of the limestone and forms a very rm bond therewith and the, rough and jaggedcondition of the'constituent parts of the aggregate also assists informing a tight bond.- The material of the aggregate should be as freefrom clay as possible, since the presence of. clay will produce aslippery pavement. After rolling with the light roller, I apply a topdressing of about eth inch 'pieces of aggregate consisting of crushedhard rock such as basalt or granite, lime rock and pumice stone, whichfills up the larger voids on the upper surface. This is then rolled witha heavy steam roller, the roller of which is preferably heated and -theincrease in pressure compacts the aggregate more closely, forcing someof the asphalt up and thereby binding the top dressing in place. Thelime rock in the top dressing is adhered to very strongly by the asphaltproducing a very stable pavement and the pumice stone is present toabsorb aofthe lubricatingoil which subsequently falls on the pavement.The finished pavement presents a substantiallysmooth, hard sur I facehaving innumerable small depressions longitudinally therein is providedfor the -distribution of the hot liquid asphalt.

Behind this conductor is a similar one for dis tributing the asphaltmixture on the asphalt coat and behind this is a rotating screen orshuttle or other device for depositing the agegate.

I claim: I

1. In a street pavement, an asphaltic min eral structure composed ofcrushed hard rock, lime stone, an oil absorbing stone andan asphalticbinder.

2. In a street pavement, an asphaltic mineral structure composed ofcrushed hard rock, -lime' stone, 'pumice stone. and an' asphalticbinder.

3. A street pavement comprising a rigid foundation, a coatin'gff ofasphalt on said foundation, a coating of asphalt mixture"- consisting ofasphalt, ground lime stone, ground oil absorbing stone and an asphalticbinder on said asphalt'coating, and a layer of mineral aggregate ofsmall sizes and free from clay on said asphalt mixture, the aggregatebeing rolled to force the asphaltupward'into the interstices of theaggregate.

4. In a street pavement, a wearing surface containing crushed limestone, pumice stone and a binder. V p

'5. The method of constructing a wearing surface on a road foundationwhich consists in applying a coat of hot liquid asphalt, then applying acoat of a hot liquid asphalt mixture consisting of asphalt, ground limestone, ground oil absorbin'g'stone and an asphaltic binder, thenapplying a .layer of hot crushed mineral aggregate. and-then I rollingthe mass with a hot roller.

6. The method of constructinga wearing surface on a road foundationwhichconsists in applying a coat. of hot liquid asphalt, then applying acoat of an asphalt mixture containing -st ffening andoil absorbingmediums and afiller, then applying a layer of hot crushed mineralaggregate, the separate pieces of which will pass through a three-,eighths inch ring, then rolling: the mass with a hot roller to forcethe asphalt upward into the interstices in the aggregate.

.7. Themethod of constructingawearing surface on a road foundation whichconsists in applying a coat of hot liquid asphalt,

then applying a coat of hotliquid asphalt containingplaster of Paris,then applying a layer of crushed mineral aggregate containing limestone, then rolling the mass, then applying a top'dressing of finemineral avggregate containing an oil absorbing mineral and then rollingthe 1nass with: a heavy roller.

8. The method of constructing a wearing surface on old asphalt.pavements which consists in heating the surface of' the old pavement,applying a coat of, hot liquid asphalt thereto, then applying a coat ofhot liquid asphalt containing plaster ofIaris,

then applying a layer of hot mineral aggre gate free from clay andcontaining lime stone, then rolling the mass with a hot roller, thenapplying a top dressing of fine mineral aggregate free from clay andcontaining,

lime stone and pumice stone, and then rolling the mass with aheavyroller;

In testimony whereof, I have hereunto set my hand at San Francisco,California, this 8th day of September, 1913.

JOSEPH SGHEERER. In presence of H. G. PRosT, M. LE CONTE.

